1. Field of the Invention
The invention generally relates to an electromagnetically driven valve and, more particularly, to a pivot-type electromagnetically driven valve for use in an internal combustion engine which is driven by elastic force and electromagnetic force.
2. Description of the Related Art
Related-art electromagnetically driven valves are disclosed in, for example, U.S. Pat. No. 6,467,441.
In the case where a related-art electromagnetically driven valve employs a plurality of discs, there is a problem that precision control cannot be achieved if it is attempted to control the valve by sensing the movement of a single disc via a single sensor, since the discs do not move uniformly due to dimensional tolerances and mounting precision.
Another problem with the related art is that when the discs are in a neutral position, the air gap is large, and the valve cannot be moved easily unless increased electric power is supplied.
Still another problem is that, due to variations in dimensions and mounting precision, the core and the discs do not make completely close contact with each other, and therefore fail to obtain desired electromagnetic force, resulting in unstable operation of the valve.